Many electric machines, such as electric motors and generators, among others, generate internal heat while operating. In many cases, this heat has to be continuously removed from the electric machine to prevent an undue increase in temperature that can make the device perform unsatisfactorily or even lead to device failure.
In these cases, a cooling device is connected to the electric machine to draw away excess heat. The cooling device typically includes means for dissipating the heat, such as, for example, fins, heat pipes or passageways suitable for allowing the circulation of a cooling fluid.
To draw heat from the electric machine, the cooling device has to be in physical contact with, and at a lower temperature than, the electric machine. Prior to operating, the cooling device and the motor are at a common temperature. However, because they differ in temperatures when operating, the electric machine typically undergoes a thermal expansion different from a thermal expansion of the cooling device. This difference in thermal expansion may render the physical contact between the electric machine and the cooling device unsatisfactory.
To solve that problem, it is well known in the art to glue the cooling device to the electric machine with a heat-conducting adhesive. However, if the cooling device is inserted inside a cavity defined by the electric machine, the adhesive may not be strong enough to ensure that the physical contact is maintained. This may happen because the cooling device, as its temperature is lower, will typically expand less than the operating electric machine. Consequently, the cavity might become large enough to overwhelm the adhesive capacity of the adhesive.
Against this background, there exists a need in the industry to provide a novel cooling device for an electric machine.